1. Field of the Invention
The present invention relates to a communication apparatus using a called terminal identifier or a calling terminal identifier (to be referred to as a TiD hereinafter) in a communication procedure.
2. Related Background Art
As a conventional apparatus of this type, a facsimile apparatus of Group 4 (G4) of the CCITT recommendation is known.
In some G4 facsimile apparatuses, special communication modes such as a closed network communication mode, a polling mode, a confidential communication mode, and the like are available. Such special communication modes are set by utilizing non-standardized capabilities (to be referred to as NSC hereinafter) in the communication procedure.
However, since the above-mentioned NSCs can be desirably set by manufacturers, they have different formats in units of types of apparatuses. For this reason, when the types of apparatuses are different (in particular, when manufacturers are different), communications in the above-mentioned special communication modes cannot be performed.
Thus, according to the present invention, when a communication is performed in one of the above-mentioned special communication modes, whether or not the TiD of a station to be called is registered is checked to allow a special communication in only a communication with a specific station. When the TiD of the station is registered, the above-mentioned special communication is allowed.
In this case, whether or not the TiD of a given station to be called coincides with a registered TiD is checked. At this time, however, when it is checked if the two TiDs perfectly coincide with each other, the following problems are pose.
(1) In a TiD checking operation performed when various communication modes are realized by checking TiDs at calling and called stations, if capital letters and small letters are distinguished from each other, the degree of freedom of a TiD input at a called station is limited. For example, it cannot be determined that TiDs "081-12345=ABCD" and "081-12345=Abcd" coincide with each other.
(2) In the TiD checking operation performed when various communication modes are realized by checking TiDs at calling and called stations, the degree of freedom of a TiD input at a called station is limited. For example, it cannot be determined that TiDs "081-12345=ABCD" and "081-12345=AbcdInc" coincide with each other.
It cannot also be determined that "081-12345=Ashop" and "081-12345=Bshop" coincide with each other.
As applications for collating telephone numbers, there are U.S. Pat. application Ser. No. 289,014 (filed on Dec. 23, 1988, now U.S. Pat. No. 5,239,385), U.S. patent application Ser. No. 442,721 (filed on Nov. 29, 1989, now abandoned) , and U.S. patent application Ser. No. 547,127 (filed on Jul. 3, 1990, now abandoned). However, no applications that can solve the above-mentioned problems have been proposed yet.